A voltage control method suitable for flexible DC distribution network

Abstract

The invention relates to a voltage control method applied to a flexible DC power distribution network, which belongs to the technical field of DC power distribution system voltage control. According to the method, a master station adopts constant voltage and constant reactive power control, the master station serves as a slack bus to control system DC voltage, a voltage reference value is provided for the overall DC power distribution network, and when an AC system fails, reactive power support is provided for the AC side. A slave station adopts a P-U-I controller; when the system operates in a steady state, a converter station VSC is in a power control mode PQ, the power is adjustable, the voltage is controllable, power ring control P adjusts output of the VSC according to a system power optimization instruction sent by an energy management system EMS and distribution network power flow is optimized. When the system is in a transient state, the VSC is in a VdcQ mode, voltage ring control U maintains system DC voltage, and the system operates in a rated voltage upper limit and a lower limit. The voltage control method applied to the flexible DC power distribution network has the advantages that the structure is simple, gradation is distinct, realization is easy, the hardware communication cost is greatly saved, system control is simplified, and adaptation and expandability are wide.

Description

technical field [0001] The invention relates to a voltage control method suitable for a flexible direct current distribution network, which is a control method for regulating the energy of the direct current distribution network and controlling the voltage of the direct current distribution network, and belongs to the technical field of voltage control of the direct current distribution system. Background technique [0002] In recent years, with the continuous expansion of cities, distributed power sources, high-density access to renewable energy, and the vigorous development of information technology and power electronics technology, the use of DC distribution networks can save a lot of DC / AC commutation links, Improve the power and efficiency of line transmission, increase the power supply capacity and radius of the system, and have certain environmental protection advantages. At the same time, users' requirements for power quality and power supply reliability continue to i...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the problem that the VSC faces complex mode switching due to the change of the operation mode of the DC distribution network system, the present invention proposes a voltage control method suitable for the flexible DC distribution network. After the operation mode changes, it can automatically realize the seamless switching of the VSC working mode, reducing the system's requirements for communication detection

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